"Bird's Nest Fern" (Asplenium nidus) is commonly grown as a landscaping plant in Florida, Texas, Arizona and California. It is hardy between U.S. Department of Agriculture plant hardiness zones 9 to 11, and is grown as a houseplant elsewhere. Brown leaf edges may indicate a cultural problem or disease and in most cases is easy to treat.
Lack of Water
Like most ferns, "Bird's Nest" ferns are not drought tolerant and require evenly moist soil at all times. Without sufficient water, the tips of the leaves may turn brown. Increase water to reduce tip burn, but ensure that the soil is well-draining, because Bird's Nest ferns don't tolerate wet, heavy soils.
Too much fertiliser may be the cause of leaf tip burn, especially in houseplants. Salts from the fertiliser accumulate in the soil, causing the leaves to turn brown. Reduce the amount of fertiliser, using a diluted water-soluble solution only every three to four weeks. Water the soil well to leach the salts out of it.
Bacterial wilt starts as small, transparent spots on the leaves. As the disease spreads, the lesions cover the entire leaf and turn brown or purple. No effective cure exists for bacterial wilt. Start with disease-free plants and avoid wetting the leaves. Discard diseased plants.
Several insects attack "Bird's Nest" ferns, including mites, slugs, snails and mealybugs. These insects may cause brown spots on the leaves, but are more likely to make holes in the leaves, or leave behind physical signs of infestation, such as sticky honeydew or a white cottony substance. Affected plants may wither or become stunted.